(function(){

this.DatePicker = Picker.Date = new Class({

	Extends: Picker.Attach,

	options: {/*
		onSelect: function(date){},

		minDate: new Date('3/4/2010'), // Date object or a string
		maxDate: new Date('3/4/2011'), // same as minDate
		availableDates: {}, //
		invertAvailable: false,

		format: null,*/

		timePicker: false,
		timePickerOnly: false, // deprecated, use onlyView = 'time'
		timeWheelStep: 1, // 10,15,20,30

		yearPicker: true,
		yearsPerPage: 20,

		startDay: 1, // Sunday (0) through Saturday (6) - be aware that this may affect your layout, since the days on the right might have a different margin
		rtl: false,

		startView: 'days', // allowed values: {time, days, months, years}
		openLastView: false,
		pickOnly: false, // 'years', 'months', 'days', 'time'
		canAlwaysGoUp: ['months', 'days'],
		updateAll : false, //whether or not to update all inputs when selecting a date

		weeknumbers: false,

		// if you like to use your own translations
		months_abbr: null,
		days_abbr: null,
		years_title: function(date, options){
			var year = date.get('year');
			return year + '-' + (year + options.yearsPerPage - 1);
		},
		months_title: function(date, options){
			return date.get('year');
		},
		days_title: function(date, options){
			return date.format('%b %Y');
		},
		time_title: function(date, options){
			return (options.pickOnly == 'time') ? Locale.get('DatePicker.select_a_time') : date.format('%d %B, %Y');
		}
	},

	initialize: function(attachTo, options){
		this.parent(attachTo, options);

		this.setOptions(options);
		options = this.options;

		// If we only want to use one picker / backwards compatibility
		['year', 'month', 'day', 'time'].some(function(what){
			if (options[what + 'PickerOnly']){
				options.pickOnly = what;
				return true;
			}
			return false;
		});
		if (options.pickOnly){
			options[options.pickOnly + 'Picker'] = true;
			options.startView = options.pickOnly;
		}

		// backward compatibility for startView
		var newViews = ['days', 'months', 'years'];
		['month', 'year', 'decades'].some(function(what, i){
			return (options.startView == what) && (options.startView = newViews[i]);
		});

		options.canAlwaysGoUp = options.canAlwaysGoUp ? Array.from(options.canAlwaysGoUp) : [];

		// Set the min and max dates as Date objects
		if (options.minDate){
			if (!(options.minDate instanceof Date)) options.minDate = Date.parse(options.minDate);
			options.minDate.clearTime();
		}
		if (options.maxDate){
			if (!(options.maxDate instanceof Date)) options.maxDate = Date.parse(options.maxDate);
			options.maxDate.clearTime();
		}

		if (!options.format){
			options.format = (options.pickOnly != 'time') ? Locale.get('Date.shortDate') : '';
			if (options.timePicker) options.format = (options.format) + (options.format ? ' ' : '') + Locale.get('Date.shortTime');
		}

		// Some link or input has fired an event!
		this.addEvent('attached', function(event, element){

			// This is where we store the selected date
			if (!this.currentView || !options.openLastView) this.currentView = options.startView;

			this.date = limitDate(new Date(), options.minDate, options.maxDate);
			var tag = element.get('tag'), input;
			if (tag == 'input') input = element;
			else {
				var index = this.toggles.indexOf(element);
				if (this.inputs[index]) input = this.inputs[index];
			}
			this.getInputDate(input);
			this.input = input;
			this.setColumns(this.originalColumns);
		}.bind(this), true);

	},

	getInputDate: function(input){
		this.date = new Date();
		if (!input) return;
		var date = Date.parse(input.get('value'));
		if (date == null || !date.isValid()){
			var storeDate = input.retrieve('datepicker:value');
			if (storeDate) date = Date.parse(storeDate);
		}
		if (date != null && date.isValid()) this.date = date;
	},

	// Control the previous and next elements

	constructPicker: function(){
		this.parent();

		if (!this.options.rtl){
			this.previous = new Element('div.previous[html=&#171;]').inject(this.header);
			this.next = new Element('div.next[html=&#187;]').inject(this.header);
		} else {
			this.next = new Element('div.previous[html=&#171;]').inject(this.header);
			this.previous = new Element('div.next[html=&#187;]').inject(this.header);
		}
	},

	hidePrevious: function(_next, _show){
		this[_next ? 'next' : 'previous'].setStyle('display', _show ? 'block' : 'none');
		return this;
	},

	showPrevious: function(_next){
		return this.hidePrevious(_next, true);
	},

	setPreviousEvent: function(fn, _next){
		this[_next ? 'next' : 'previous'].removeEvents('click');
		if (fn) this[_next ? 'next' : 'previous'].addEvent('click', fn);
		return this;
	},

	hideNext: function(){
		return this.hidePrevious(true);
	},

	showNext: function(){
		return this.showPrevious(true);
	},

	setNextEvent: function(fn){
		return this.setPreviousEvent(fn, true);
	},

	setColumns: function(columns, view, date, viewFx){
		var ret = this.parent(columns), method;

		if ((view || this.currentView)
			&& (method = 'render' + (view || this.currentView).capitalize())
			&& this[method]
		) this[method](date || this.date.clone(), viewFx);

		return ret;
	},

	// Render the Pickers

	renderYears: function(date, fx){
		var options = this.options, pages = options.columns, perPage = options.yearsPerPage,
			_columns = [], _dates = [];
		this.dateElements = [];

		// start neatly at interval (eg. 1980 instead of 1987)
		date = date.clone().decrement('year', date.get('year') % perPage);
	
		var iterateDate = date.clone().decrement('year', Math.floor((pages - 1) / 2) * perPage);

		for (var i = pages; i--;){
			var _date = iterateDate.clone();
			_dates.push(_date);
			_columns.push(renderers.years(
				timesSelectors.years(options, _date.clone()),
				options,
				this.date.clone(),
				this.dateElements,
				function(date){
					if (options.pickOnly == 'years') this.select(date);
					else this.renderMonths(date, 'fade');
					this.date = date;
				}.bind(this)
			));
			iterateDate.increment('year', perPage);
		}

		this.setColumnsContent(_columns, fx);
		this.setTitle(_dates, options.years_title);

		// Set limits
		var limitLeft = (options.minDate && date.get('year') <= options.minDate.get('year')),
			limitRight = (options.maxDate && (date.get('year') + options.yearsPerPage) >= options.maxDate.get('year'));
		this[(limitLeft ? 'hide' : 'show') + 'Previous']();
		this[(limitRight ? 'hide' : 'show') + 'Next']();

		this.setPreviousEvent(function(){
			this.renderYears(date.decrement('year', perPage), 'left');
		}.bind(this));

		this.setNextEvent(function(){
			this.renderYears(date.increment('year', perPage), 'right');
		}.bind(this));

		// We can't go up!
		this.setTitleEvent(null);

		this.currentView = 'years';
	},

	renderMonths: function(date, fx){
		var options = this.options, years = options.columns, _columns = [], _dates = [],
			iterateDate = date.clone().decrement('year', Math.floor((years - 1) / 2));
		this.dateElements = [];

		for (var i = years; i--;){
			var _date = iterateDate.clone();
			_dates.push(_date);
			_columns.push(renderers.months(
				timesSelectors.months(options, _date.clone()),
				options,
				this.date.clone(),
				this.dateElements,
				function(date){
					if (options.pickOnly == 'months') this.select(date);
					else this.renderDays(date, 'fade');
					this.date = date;
				}.bind(this)
			));
			iterateDate.increment('year', 1);
		}

		this.setColumnsContent(_columns, fx);
		this.setTitle(_dates, options.months_title);

		// Set limits
		var year = date.get('year'),
			limitLeft = (options.minDate && year <= options.minDate.get('year')),
			limitRight = (options.maxDate && year >= options.maxDate.get('year'));
		this[(limitLeft ? 'hide' : 'show') + 'Previous']();
		this[(limitRight ? 'hide' : 'show') + 'Next']();

		this.setPreviousEvent(function(){
			this.renderMonths(date.decrement('year', years), 'left');
		}.bind(this));

		this.setNextEvent(function(){
			this.renderMonths(date.increment('year', years), 'right');
		}.bind(this));

		var canGoUp = options.yearPicker && (options.pickOnly != 'months' || options.canAlwaysGoUp.contains('months'));
		var titleEvent = (canGoUp) ? function(){
			this.renderYears(date, 'fade');
		}.bind(this) : null;
		this.setTitleEvent(titleEvent);

		this.currentView = 'months';
	},

	renderDays: function(date, fx){
		var options = this.options, months = options.columns, _columns = [], _dates = [],
			iterateDate = date.clone().decrement('month', Math.floor((months - 1) / 2));
		this.dateElements = [];

		for (var i = months; i--;){
			_date = iterateDate.clone();
			_dates.push(_date);
			_columns.push(renderers.days(
				timesSelectors.days(options, _date.clone()),
				options,
				this.date.clone(),
				this.dateElements,
				function(date){
					if (options.pickOnly == 'days' || !options.timePicker) this.select(date)
					else this.renderTime(date, 'fade');
					this.date = date;
				}.bind(this)
			));
			iterateDate.increment('month', 1);
		}

		this.setColumnsContent(_columns, fx);
		this.setTitle(_dates, options.days_title);

		var yearmonth = date.format('%Y%m').toInt(),
			limitLeft = (options.minDate && yearmonth <= options.minDate.format('%Y%m')),
			limitRight = (options.maxDate && yearmonth >= options.maxDate.format('%Y%m'));
		this[(limitLeft ? 'hide' : 'show') + 'Previous']();
		this[(limitRight ? 'hide' : 'show') + 'Next']();

		this.setPreviousEvent(function(){
			this.renderDays(date.decrement('month', months), 'left');
		}.bind(this));

		this.setNextEvent(function(){
			this.renderDays(date.increment('month', months), 'right');
		}.bind(this));

		var canGoUp = options.pickOnly != 'days' || options.canAlwaysGoUp.contains('days');
		var titleEvent = (canGoUp) ? function(){
			this.renderMonths(date, 'fade');
		}.bind(this) : null;
		this.setTitleEvent(titleEvent);

		this.currentView = 'days';
	},

	renderTime: function(date, fx){
		var options = this.options;
		this.setTitle(date, options.time_title);

		var originalColumns = this.originalColumns = options.columns;
		this.currentView = null; // otherwise you'd get crazy recursion
		if (originalColumns != 1) this.setColumns(1);

		this.setContent(renderers.time(
			options,
			date.clone(),
			function(date){
				this.select(date);
			}.bind(this)
		), fx);

		// Hide « and » buttons
		this.hidePrevious()
			.hideNext()
			.setPreviousEvent(null)
			.setNextEvent(null);

		var canGoUp = options.pickOnly != 'time' || options.canAlwaysGoUp.contains('time');
		var titleEvent = (canGoUp) ? function(){
			this.setColumns(originalColumns, 'days', date, 'fade');
		}.bind(this) : null;
		this.setTitleEvent(titleEvent);

		this.currentView = 'time';
	},

	select: function(date, all){
		this.date = date;
		var formatted = date.format(this.options.format),
			time = date.strftime(),
			inputs = (!this.options.updateAll && !all && this.input) ? [this.input] : this.inputs;

		inputs.each(function(input){
			input.set('value', formatted).store('datepicker:value', time).fireEvent('change');
		}, this);

		this.fireEvent('select', [date].concat(inputs));
		this.close();
		return this;
	}

});


// Renderers only output elements and calculate the limits!

var timesSelectors = {

	years: function(options, date){
		var times = [];
		for (var i = 0; i < options.yearsPerPage; i++){
			times.push(+date);
			date.increment('year', 1);
		}
		return times;
	},

	months: function(options, date){
		var times = [];
		date.set('month', 0);
		for (var i = 0; i <= 11; i++){
			times.push(+date);
			date.increment('month', 1);
		}
		return times;
	},

	days: function(options, date){
		var times = [];
		date.set('date', 1);
		while (date.get('day') != options.startDay) date.set('date', date.get('date') - 1);
		for (var i = 0; i < 42; i++){
			times.push(+date);
			date.increment('day',  1);
		}
		return times;
	}

};

var renderers = {

	years: function(years, options, currentDate, dateElements, fn){
		var container = new Element('div.years'),
			today = new Date(), element, classes;

		years.each(function(_year, i){
			var date = new Date(_year), year = date.get('year');

			classes = '.year.year' + i;
			if (year == today.get('year')) classes += '.today';
			if (year == currentDate.get('year')) classes += '.selected';
			element = new Element('div' + classes, {text: year}).inject(container);

			dateElements.push({element: element, time: _year});

			if (isUnavailable('year', date, options)) element.addClass('unavailable');
			else element.addEvent('click', fn.pass(date));
		});

		return container;
	},

	months: function(months, options, currentDate, dateElements, fn){
		var today = new Date(),
			month = today.get('month'),
			thisyear = today.get('year'),
			selectedyear = currentDate.get('year'),
			container = new Element('div.months'),
			monthsAbbr = options.months_abbr || Locale.get('Date.months_abbr'),
			element, classes;

		months.each(function(_month, i){
			var date = new Date(_month), year = date.get('year');

			classes = '.month.month' + (i + 1);
			if (i == month && year == thisyear) classes += '.today';
			if (i == currentDate.get('month') && year == selectedyear) classes += '.selected';
			element = new Element('div' + classes, {text: monthsAbbr[i]}).inject(container);

			dateElements.push({element: element, time: _month});

			if (isUnavailable('month', date, options)) element.addClass('unavailable');
			else element.addEvent('click', fn.pass(date));
		});

		return container;
	},

	days: function(days, options, currentDate, dateElements, fn){
		var month = new Date(days[14]).get('month'),
			todayString = new Date().toDateString(),
			currentString = currentDate.toDateString(),
			weeknumbers = options.weeknumbers,
			container = new Element('table.days' + (weeknumbers ? '.weeknumbers' : ''), {
				role: 'grid', 'aria-labelledby': this.titleID
			}),
			header = new Element('thead').inject(container),
			body = new Element('tbody').inject(container),
			titles = new Element('tr.titles').inject(header),
			localeDaysShort = options.days_abbr || Locale.get('Date.days_abbr'),
			day, classes, element, weekcontainer, dateString,
			where = options.rtl ? 'top' : 'bottom';

		if (weeknumbers) new Element('th.title.day.weeknumber', {
			text: Locale.get('DatePicker.week')
		}).inject(titles);

		for (day = options.startDay; day < (options.startDay + 7); day++){
			new Element('th.title.day.day' + (day % 7), {
				text: localeDaysShort[(day % 7)],
				role: 'columnheader'
			}).inject(titles, where);
		}

		days.each(function(_date, i){
			var date = new Date(_date);

			if (i % 7 == 0){
				weekcontainer = new Element('tr.week.week' + (Math.floor(i / 7))).set('role', 'row').inject(body);
				if (weeknumbers) new Element('th.day.weeknumber', {text: date.get('week'), scope: 'row', role: 'rowheader'}).inject(weekcontainer);
			}

			dateString = date.toDateString();
			classes = '.day.day' + date.get('day');
			if (dateString == todayString) classes += '.today';
			if (date.get('month') != month) classes += '.otherMonth';
			element = new Element('td' + classes, {text: date.getDate(), role: 'gridcell'}).inject(weekcontainer, where);

			if (dateString == currentString) element.addClass('selected').set('aria-selected', 'true');
			else element.set('aria-selected', 'false');

			dateElements.push({element: element, time: _date});

			if (isUnavailable('date', date, options)) element.addClass('unavailable');
			else element.addEvent('click', fn.pass(date.clone()));
		});

		return container;
	},

	time: function(options, date, fn){
		var container = new Element('div.time'),
			// make sure that the minutes are timeWheelStep * k
			initMinutes = (date.get('minutes') / options.timeWheelStep).round() * options.timeWheelStep

		if (initMinutes >= 60) initMinutes = 0;
		date.set('minutes', initMinutes);

		var hoursInput = new Element('input.hour[type=text]', {
			title: Locale.get('DatePicker.use_mouse_wheel'),
			value: date.format('%H'),
			events: {
				click: function(event){
					event.target.focus();
					event.stop();
				},
				mousewheel: function(event){
					event.stop();
					hoursInput.focus();
					var value = hoursInput.get('value').toInt();
					value = (event.wheel > 0) ? ((value < 23) ? value + 1 : 0)
						: ((value > 0) ? value - 1 : 23)
					date.set('hours', value);
					hoursInput.set('value', date.format('%H'));
				}.bind(this)
			},
			maxlength: 2
		}).inject(container);

		var minutesInput = new Element('input.minutes[type=text]', {
			title: Locale.get('DatePicker.use_mouse_wheel'),
			value: date.format('%M'),
			events: {
				click: function(event){
					event.target.focus();
					event.stop();
				},
				mousewheel: function(event){
					event.stop();
					minutesInput.focus();
					var value = minutesInput.get('value').toInt();
					value = (event.wheel > 0) ? ((value < 59) ? (value + options.timeWheelStep) : 0)
						: ((value > 0) ? (value - options.timeWheelStep) : (60 - options.timeWheelStep));
					if (value >= 60) value = 0;
					date.set('minutes', value);
					minutesInput.set('value', date.format('%M'));
				}.bind(this)
			},
			maxlength: 2
		}).inject(container);

		new Element('div.separator[text=:]').inject(container);

		new Element('input.ok[type=submit]', {
			value: Locale.get('DatePicker.time_confirm_button'),
			events: {click: function(event){
				event.stop();
				date.set({
					hours: hoursInput.get('value').toInt(),
					minutes: minutesInput.get('value').toInt()
				});
				fn(date.clone());
			}}
		}).inject(container);

		return container;
	}

};


Picker.Date.defineRenderer = function(name, fn){
	renderers[name] = fn;
	return this;
};

var limitDate = function(date, min, max){
	if (min && date < min) return min;
	if (max && date > max) return max;
	return date;
};

var isUnavailable = function(type, date, options){
	var minDate = options.minDate,
		maxDate = options.maxDate,
		availableDates = options.availableDates,
		year, month, day, ms;

	if (!minDate && !maxDate && !availableDates) return false;
	date.clearTime();

	if (type == 'year'){
		year = date.get('year');
		return (
			(minDate && year < minDate.get('year')) ||
			(maxDate && year > maxDate.get('year')) ||
			(
				(availableDates != null &&  !options.invertAvailable) && (
					availableDates[year] == null ||
					Object.getLength(availableDates[year]) == 0 ||
					Object.getLength(
						Object.filter(availableDates[year], function(days){
							return (days.length > 0);
						})
					) == 0
				)
			)
		);
	}

	if (type == 'month'){
		year = date.get('year');
		month = date.get('month') + 1;
		ms = date.format('%Y%m').toInt();
		return (
			(minDate && ms < minDate.format('%Y%m').toInt()) ||
			(maxDate && ms > maxDate.format('%Y%m').toInt()) ||
			(
				(availableDates != null && !options.invertAvailable) && (
					availableDates[year] == null ||
					availableDates[year][month] == null ||
					availableDates[year][month].length == 0
				)
			)
		);
	}

	// type == 'date'
	year = date.get('year');
	month = date.get('month') + 1;
	day = date.get('date');

	var dateAllow = (minDate && date < minDate) || (minDate && date > maxDate);
	if (availableDates != null){
		dateAllow = dateAllow
			|| availableDates[year] == null
			|| availableDates[year][month] == null
			|| !availableDates[year][month].contains(day);
		if (options.invertAvailable) dateAllow = !dateAllow;
	}

	return dateAllow;
};

})();
